Leaf It Alone

One of the reasons I’m so interested in using native plants in our landscaping is to restore life to our property.  The insects that can only live on the native plants are a major part of the food web, bringing in birds which eat these protein morsels and feed them to their young.  Like many I've learned that the fall generation of Monarch butterflies migrates to Mexico.  I never thought about what other butterflies and insects do during our cold winter months. 

Children Playing in the Leaves
(photo by Susan Bibler)

When I was a youngster and the fall bounty of multicolored leaves started to fall, I had such great fun jumping in and out of the leaves raked into large piles by my parents.  As I grew a little, it became part of my chores to perform this fall cleanup.  Somehow it just wasn’t as much fun playing in the leaves when I had to rake them up over and over again.  For years in the fall I used to rake all the leaves to the street where the city picked them up and took them away.  Later I learned the soil could really use this organic matter that I was sending away.  Early in the fall when the leaf drop wasn’t too much, I’d run the mower over them, shredding them into small pieces and letting this organic material work its way into the ground and decompose.  When the fallen leaf cover got too thick for that, I’d shred them with a leaf blower attachment and use them for mulch or put them into the compost pile.  But things changed for me this past year. 

Polyphemus Moth

Two years ago I had fun raising some Polyphemus moths from eggs Candy Sarikonda had given me.  When they hatched, I pulled some leaves from each of their native larval host plants and let the little guys and gals decide what they liked best.  This sample included oak, black cherry, elm, locust, and maple.  Overwhelmingly they chose oak as their food of choice.  Over the course of the summer and early fall, they grew.  Wow did they grow!   They became total eating machines for a good part of the summer.  These caterpillars ate and ate.  Five times they outgrew their skins, and shedding them to allow for more growth.  Eventually they decided they were ready for the next phase of their lives and they spun cocoons (moths made cocoons, butterflies make chrysalis).  As part of this process, they wrapped leaves around themselves, providing an excellent hiding place.  Most of them emerged within a month.  After letting their wings expand and dry for 24 hours we released them.  Although they were able to fly within several hours after emergence, allowing this extra time to let their wings become strong gave them a better chance of evading predators.  Since these moths have no mouth parts, they only live three to five days.  Their sole purpose at this point is to mate and propagate.

Several of the cocoon-wrapped pupas showed signs of emerging but the weather got cold and they didn’t emerge.  Candy told me they would overwinter in their cocoons and I should expect them to merge in the spring around Easter time.  And on one bright warming spring day, there was a flutter of wings in the cage.  They had successful survived that brutally cold winter. 

Like many of the Giant silkmoths (the group to which the Polyphemus, Cecropia, and Luna moths
belong) and many other insects, they wrap themselves up in leaves for a good winter’s nap.  Take a look at this group of leaves.  Only by turning them over and carefully looking would you be able to see the well hidden Polyphemus cocoon.  (See a larger photo essay about these stunning moths at https://www.dropbox.com/s/w6bilvu8mx9wi2e/Polyphemus%20Moth%20-%20leaves.pdf?dl=0)

Polyphemus Cocoons hidden in Leaves

Without careful inspection you’d never even notice these overwintering creatures hidden in your leaves.  You can imagine what shredding the leaves would do to these creatures.  If you rake your leaves into your garden, or loosely arrange them around your trees and shrubs you’ll be saving these fascinating moths from certain death.

This year as leaves start to coat my yard, I’m raking them into the garden beds and forgoing shredding.   And now that I think about it, it’s a whole lot less work for me.  Good for the moths, good for me.